Java tutorial
/* * Copyright (C) 2011 Patrik kerfeldt * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.jp.fristandroidapp.widget.adview; import android.content.Context; import android.content.res.Configuration; import android.content.res.TypedArray; import android.database.DataSetObserver; import android.os.Handler; import android.os.Message; import android.support.v4.view.ViewPager; import android.support.v4.widget.SlidingPaneLayout; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewTreeObserver.OnGlobalLayoutListener; import android.widget.AbsListView; import android.widget.Adapter; import android.widget.AdapterView; import android.widget.ScrollView; import android.widget.Scroller; import com.jp.fristandroidapp.R; import java.util.ArrayList; import java.util.LinkedList; /** * * A horizontally scrollable {@link android.view.ViewGroup} with items populated from an * {@link Adapter}. The ViewFlow uses a buffer to store loaded {@link View}s in. * The default size of the buffer is 3 elements on both sides of the currently * visible {@link View}, making up a total buffer size of 3 * 2 + 1 = 7. The * buffer size can be changed using the {@code sidebuffer} xml attribute. * * @author http://blog.csdn.net/finddreams */ public class AdViewFlow extends AdapterView<Adapter> { private static final int SNAP_VELOCITY = 1000; private static final int INVALID_SCREEN = -1; private final static int TOUCH_STATE_REST = 0; private final static int TOUCH_STATE_SCROLLING = 1; private LinkedList<View> mLoadedViews; private int mCurrentBufferIndex; private int mCurrentAdapterIndex; private int mSideBuffer = 0; private Scroller mScroller; private VelocityTracker mVelocityTracker; private int mTouchState = TOUCH_STATE_REST; private float mLastMotionX; private int mTouchSlop; private int mMaximumVelocity; private int mCurrentScreen; private int mNextScreen = INVALID_SCREEN; private boolean mFirstLayout = true; private ViewSwitchListener mViewSwitchListener; private Adapter mAdapter; private int mLastScrollDirection; private AdapterDataSetObserver mDataSetObserver; private FlowIndicator mIndicator; private int mLastOrientation = -1; private long timeSpan = 3000; private Handler handler; private OnGlobalLayoutListener orientationChangeListener = new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { getViewTreeObserver().removeGlobalOnLayoutListener(orientationChangeListener); setSelection(mCurrentAdapterIndex); } }; private AbsListView mLvParent; private ScrollView mScrollView; public void setmLvParent(AbsListView mLvParent) { this.mLvParent = mLvParent; } public void setScrollView(ScrollView mLvParent) { this.mScrollView = mLvParent; } private ViewPager mArea2; public void setmArea2(ViewPager area2) { this.mArea2 = area2; } private SlidingPaneLayout mArea3; public void setmArea3(SlidingPaneLayout area3) { this.mArea3 = area3; } /** * Receives call backs when a new {@link View} has been scrolled to. */ public static interface ViewSwitchListener { /** * This method is called when a new View has been scrolled to. * * @param view * the {@link View} currently in focus. * @param position * The position in the adapter of the {@link View} currently in focus. */ void onSwitched(View view, int position); } public AdViewFlow(Context context) { super(context); mSideBuffer = 0; init(); } public AdViewFlow(Context context, int sideBuffer) { super(context); mSideBuffer = sideBuffer; init(); } public AdViewFlow(Context context, AttributeSet attrs) { super(context, attrs); TypedArray styledAttrs = context.obtainStyledAttributes(attrs, R.styleable.ViewFlow); mSideBuffer = styledAttrs.getInt(R.styleable.ViewFlow_sidebuffer, 0); init(); } private void init() { mLoadedViews = new LinkedList<View>(); mScroller = new Scroller(getContext()); final ViewConfiguration configuration = ViewConfiguration.get(getContext()); mTouchSlop = configuration.getScaledTouchSlop(); mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); } public void startAutoFlowTimer() { handler = new Handler() { @Override public void handleMessage(Message msg) { snapToScreen((mCurrentScreen + 1) % getChildCount()); Message message = handler.obtainMessage(0); sendMessageDelayed(message, timeSpan); } }; Message message = handler.obtainMessage(0); handler.sendMessageDelayed(message, timeSpan); } public void stopAutoFlowTimer() { if (handler != null) handler.removeMessages(0); handler = null; } public void onConfigurationChanged(Configuration newConfig) { if (newConfig.orientation != mLastOrientation) { mLastOrientation = newConfig.orientation; getViewTreeObserver().addOnGlobalLayoutListener(orientationChangeListener); } } public void setViewsCount(int count) { mSideBuffer = count; } public int getViewsCount() { return mSideBuffer; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int width = MeasureSpec.getSize(widthMeasureSpec); final int widthMode = MeasureSpec.getMode(widthMeasureSpec); // if (widthMode != MeasureSpec.EXACTLY && !isInEditMode()) { // throw new IllegalStateException( // "ViewFlow can only be used in EXACTLY mode."); // } final int heightMode = MeasureSpec.getMode(heightMeasureSpec); if (heightMode != MeasureSpec.EXACTLY && !isInEditMode()) { throw new IllegalStateException("ViewFlow can only be used in EXACTLY mode."); } // The children are given the same width and height as the workspace final int count = getChildCount(); for (int i = 0; i < count; i++) { getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec); } if (mFirstLayout) { mScroller.startScroll(0, 0, mCurrentScreen * width, 0, 0); mFirstLayout = false; } } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { int childLeft = 0; final int count = getChildCount(); for (int i = 0; i < count; i++) { final View child = getChildAt(i); if (child.getVisibility() != View.GONE) { final int childWidth = child.getMeasuredWidth(); child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight()); childLeft += childWidth; } } } private void setIsInterceptParent(boolean isShow) { if (mLvParent != null) { mLvParent.requestDisallowInterceptTouchEvent(isShow); } } private void setIsInterceptParent2(boolean isShow) { if (mArea2 != null) { mArea2.requestDisallowInterceptTouchEvent(isShow); } } private void setIsInterceptParent3(boolean isShow) { if (mArea3 != null) { mArea3.requestDisallowInterceptTouchEvent(isShow); } } private void setIsInterceptParent4(boolean isShow) { if (mScrollView != null) { mScrollView.requestDisallowInterceptTouchEvent(isShow); } } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if (getChildCount() == 0) return false; if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); final int action = ev.getAction(); final float x = ev.getX(); switch (action) { case MotionEvent.ACTION_DOWN: setIsInterceptParent(true); setIsInterceptParent2(true); setIsInterceptParent3(true); setIsInterceptParent4(true); /* * If being flinged and user touches, stop the fling. isFinished * will be false if being flinged. */ if (!mScroller.isFinished()) { mScroller.abortAnimation(); } // Remember where the motion event started mLastMotionX = x; mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; if (handler != null) handler.removeMessages(0); break; case MotionEvent.ACTION_MOVE: final int xDiff = (int) Math.abs(x - mLastMotionX); boolean xMoved = xDiff > mTouchSlop; if (xMoved) { // Scroll if the user moved far enough along the X axis mTouchState = TOUCH_STATE_SCROLLING; } if (mTouchState == TOUCH_STATE_SCROLLING) { // Scroll to follow the motion event final int deltaX = (int) (mLastMotionX - x); mLastMotionX = x; final int scrollX = getScrollX(); if (deltaX < 0) { if (scrollX > 0) { scrollBy(Math.max(-scrollX, deltaX), 0); } } else if (deltaX > 0) { final int availableToScroll = getChildAt(getChildCount() - 1).getRight() - scrollX - getWidth(); if (availableToScroll > 0) { scrollBy(Math.min(availableToScroll, deltaX), 0); } } return true; } break; case MotionEvent.ACTION_UP: if (mTouchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); int velocityX = (int) velocityTracker.getXVelocity(); if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) { // Fling hard enough to move left snapToScreen(mCurrentScreen - 1); } else if (velocityX < -SNAP_VELOCITY && mCurrentScreen < getChildCount() - 1) { // Fling hard enough to move right snapToScreen(mCurrentScreen + 1); } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } mTouchState = TOUCH_STATE_REST; setIsInterceptParent(false); setIsInterceptParent2(false); setIsInterceptParent3(false); setIsInterceptParent4(false); if (handler != null) { Message message = handler.obtainMessage(0); handler.sendMessageDelayed(message, timeSpan); } break; case MotionEvent.ACTION_CANCEL: mTouchState = TOUCH_STATE_REST; setIsInterceptParent(false); setIsInterceptParent2(false); setIsInterceptParent3(false); setIsInterceptParent4(false); } return false; } @Override public boolean onTouchEvent(MotionEvent ev) { if (getChildCount() == 0) return false; if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); final int action = ev.getAction(); final float x = ev.getX(); switch (action) { case MotionEvent.ACTION_DOWN: /* * If being flinged and user touches, stop the fling. isFinished * will be false if being flinged. */ if (!mScroller.isFinished()) { mScroller.abortAnimation(); } // Remember where the motion event started mLastMotionX = x; mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; if (handler != null) handler.removeMessages(0); break; case MotionEvent.ACTION_MOVE: final int xDiff = (int) Math.abs(x - mLastMotionX); boolean xMoved = xDiff > mTouchSlop; if (xMoved) { // Scroll if the user moved far enough along the X axis mTouchState = TOUCH_STATE_SCROLLING; } if (mTouchState == TOUCH_STATE_SCROLLING) { // Scroll to follow the motion event final int deltaX = (int) (mLastMotionX - x); mLastMotionX = x; final int scrollX = getScrollX(); if (deltaX < 0) { if (scrollX > 0) { scrollBy(Math.max(-scrollX, deltaX), 0); } } else if (deltaX > 0) { final int availableToScroll = getChildAt(getChildCount() - 1).getRight() - scrollX - getWidth(); if (availableToScroll > 0) { scrollBy(Math.min(availableToScroll, deltaX), 0); } } return true; } break; case MotionEvent.ACTION_UP: if (mTouchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); int velocityX = (int) velocityTracker.getXVelocity(); if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) { // Fling hard enough to move left snapToScreen(mCurrentScreen - 1); } else if (velocityX < -SNAP_VELOCITY && mCurrentScreen < getChildCount() - 1) { // Fling hard enough to move right snapToScreen(mCurrentScreen + 1); } // else if (velocityX < -SNAP_VELOCITY // && mCurrentScreen == getChildCount() - 1) { // snapToScreen(0); // } // else if (velocityX > SNAP_VELOCITY // && mCurrentScreen == 0) { // snapToScreen(getChildCount() - 1); // } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } mTouchState = TOUCH_STATE_REST; if (handler != null) { Message message = handler.obtainMessage(0); handler.sendMessageDelayed(message, timeSpan); } break; case MotionEvent.ACTION_CANCEL: snapToDestination(); mTouchState = TOUCH_STATE_REST; if (handler != null) { Message message = handler.obtainMessage(0); handler.sendMessageDelayed(message, timeSpan); } } return true; } @Override protected void onScrollChanged(int h, int v, int oldh, int oldv) { super.onScrollChanged(h, v, oldh, oldv); if (mIndicator != null) { /* * The actual horizontal scroll origin does typically not match the * perceived one. Therefore, we need to calculate the perceived * horizontal scroll origin here, since we use a view buffer. */ int hPerceived = h + (mCurrentAdapterIndex - mCurrentBufferIndex) * getWidth(); mIndicator.onScrolled(hPerceived, v, oldh, oldv); } } private void snapToDestination() { final int screenWidth = getWidth(); final int whichScreen = (getScrollX() + (screenWidth / 2)) / screenWidth; snapToScreen(whichScreen); } private void snapToScreen(int whichScreen) { mLastScrollDirection = whichScreen - mCurrentScreen; if (!mScroller.isFinished()) return; whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1)); mNextScreen = whichScreen; final int newX = whichScreen * getWidth(); final int delta = newX - getScrollX(); mScroller.startScroll(getScrollX(), 0, delta, 0, Math.abs(delta) * 2); invalidate(); } @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); postInvalidate(); } else if (mNextScreen != INVALID_SCREEN) { mCurrentScreen = Math.max(0, Math.min(mNextScreen, getChildCount() - 1)); mNextScreen = INVALID_SCREEN; postViewSwitched(mLastScrollDirection); } } /** * Scroll to the {@link View} in the view buffer specified by the index. * * @param indexInBuffer * Index of the view in the view buffer. */ private void setVisibleView(int indexInBuffer, boolean uiThread) { mCurrentScreen = Math.max(0, Math.min(indexInBuffer, getChildCount() - 1)); int dx = (mCurrentScreen * getWidth()) - mScroller.getCurrX(); mScroller.startScroll(mScroller.getCurrX(), mScroller.getCurrY(), dx, 0, 0); if (dx == 0) onScrollChanged(mScroller.getCurrX() + dx, mScroller.getCurrY(), mScroller.getCurrX() + dx, mScroller.getCurrY()); if (uiThread) invalidate(); else postInvalidate(); } /** * Set the listener that will receive notifications every time the {code * ViewFlow} scrolls. * * @param l * the scroll listener */ public void setOnViewSwitchListener(ViewSwitchListener l) { mViewSwitchListener = l; } @Override public Adapter getAdapter() { return mAdapter; } @Override public void setAdapter(Adapter adapter) { setAdapter(adapter, 0); } public void setAdapter(Adapter adapter, int initialPosition) { if (mAdapter != null) { mAdapter.unregisterDataSetObserver(mDataSetObserver); } mAdapter = adapter; if (mAdapter != null) { mDataSetObserver = new AdapterDataSetObserver(); mAdapter.registerDataSetObserver(mDataSetObserver); } if (mAdapter == null || mAdapter.getCount() == 0) return; setSelection(initialPosition); } @Override public View getSelectedView() { return (mCurrentBufferIndex < mLoadedViews.size() ? mLoadedViews.get(mCurrentBufferIndex) : null); } @Override public int getSelectedItemPosition() { return mCurrentAdapterIndex; } /** * Set the FlowIndicator * * @param flowIndicator */ public void setFlowIndicator(FlowIndicator flowIndicator) { mIndicator = flowIndicator; mIndicator.setViewFlow(this); } @Override public void setSelection(int position) { mNextScreen = INVALID_SCREEN; mScroller.forceFinished(true); if (mAdapter == null) return; position = Math.max(position, 0); position = Math.min(position, mAdapter.getCount() - 1); ArrayList<View> recycleViews = new ArrayList<View>(); View recycleView; while (!mLoadedViews.isEmpty()) { recycleViews.add(recycleView = mLoadedViews.remove()); detachViewFromParent(recycleView); } View currentView = makeAndAddView(position, true, (recycleViews.isEmpty() ? null : recycleViews.remove(0))); mLoadedViews.addLast(currentView); for (int offset = 1; mSideBuffer - offset >= 0; offset++) { int leftIndex = position - offset; int rightIndex = position + offset; if (leftIndex >= 0) mLoadedViews.addFirst( makeAndAddView(leftIndex, false, (recycleViews.isEmpty() ? null : recycleViews.remove(0)))); if (rightIndex < mAdapter.getCount()) mLoadedViews.addLast( makeAndAddView(rightIndex, true, (recycleViews.isEmpty() ? null : recycleViews.remove(0)))); } mCurrentBufferIndex = mLoadedViews.indexOf(currentView); mCurrentAdapterIndex = position; for (View view : recycleViews) { removeDetachedView(view, false); } requestLayout(); setVisibleView(mCurrentBufferIndex, false); if (mIndicator != null) { mIndicator.onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } if (mViewSwitchListener != null) { mViewSwitchListener.onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } } private void resetFocus() { mLoadedViews.clear(); removeAllViewsInLayout(); for (int i = Math.max(0, mCurrentAdapterIndex - mSideBuffer); i < Math.min(mAdapter.getCount(), mCurrentAdapterIndex + mSideBuffer + 1); i++) { mLoadedViews.addLast(makeAndAddView(i, true, null)); if (i == mCurrentAdapterIndex) mCurrentBufferIndex = mLoadedViews.size() - 1; } requestLayout(); } private void postViewSwitched(int direction) { if (direction == 0) return; if (direction > 0) { // to the right mCurrentAdapterIndex++; mCurrentBufferIndex++; // if(direction > 1) { // mCurrentAdapterIndex += mAdapter.getCount() - 2; // mCurrentBufferIndex += mAdapter.getCount() - 2; // } View recycleView = null; // Remove view outside buffer range if (mCurrentAdapterIndex > mSideBuffer) { recycleView = mLoadedViews.removeFirst(); detachViewFromParent(recycleView); // removeView(recycleView); mCurrentBufferIndex--; } // Add new view to buffer int newBufferIndex = mCurrentAdapterIndex + mSideBuffer; if (newBufferIndex < mAdapter.getCount()) mLoadedViews.addLast(makeAndAddView(newBufferIndex, true, recycleView)); } else { // to the left mCurrentAdapterIndex--; mCurrentBufferIndex--; // if(direction < -1) { // mCurrentAdapterIndex -= mAdapter.getCount() - 2; // mCurrentBufferIndex -= mAdapter.getCount() - 2; // } View recycleView = null; // Remove view outside buffer range if (mAdapter.getCount() - 1 - mCurrentAdapterIndex > mSideBuffer) { recycleView = mLoadedViews.removeLast(); detachViewFromParent(recycleView); } // Add new view to buffer int newBufferIndex = mCurrentAdapterIndex - mSideBuffer; if (newBufferIndex > -1) { mLoadedViews.addFirst(makeAndAddView(newBufferIndex, false, recycleView)); mCurrentBufferIndex++; } } requestLayout(); setVisibleView(mCurrentBufferIndex, true); if (mIndicator != null) { mIndicator.onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } if (mViewSwitchListener != null) { mViewSwitchListener.onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } } private View setupChild(View child, boolean addToEnd, boolean recycle) { LayoutParams p = (LayoutParams) child.getLayoutParams(); if (p == null) { p = new AbsListView.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT, 0); } if (recycle) attachViewToParent(child, (addToEnd ? -1 : 0), p); else addViewInLayout(child, (addToEnd ? -1 : 0), p, true); return child; } private View makeAndAddView(int position, boolean addToEnd, View convertView) { View view = mAdapter.getView(position, convertView, this); return setupChild(view, addToEnd, convertView != null); } class AdapterDataSetObserver extends DataSetObserver { @Override public void onChanged() { View v = getChildAt(mCurrentBufferIndex); if (v != null) { for (int index = 0; index < mAdapter.getCount(); index++) { if (v.equals(mAdapter.getItem(index))) { mCurrentAdapterIndex = index; break; } } } resetFocus(); } @Override public void onInvalidated() { // Not yet implemented! } } public void setTimeSpan(long timeSpan) { this.timeSpan = timeSpan; } public void setmSideBuffer(int mSideBuffer) { this.mSideBuffer = mSideBuffer; } }